Question

By default when you create a Win-Form a application, This is the code generated by visual studio to dispose the Form.

protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

Is this enough?Or I should unregister all events so the controls will be ready to collected by the garbage collector?

        if (disposing && (components != null))
        {
            myButton.OnClick-= MyFunction; //may be here!!
            // ... all events used
            components.Dispose();

        }

Answer 1

No, the garbage collector takes care of it. The event can never be raised anymore since the form instance was disposed which in turn disposed the button. There is a circular reference between the form and the button due to the event handler but the garbage collector has no trouble with them.